Extend `ResponseCache` to pass a context object into the callback (#10157)

This is the first of two PRs which seek to address #8518. This first PR lays the groundwork by extending ResponseCache; a second PR (#10158) will update the SyncHandler to actually use it, and fix the bug.

The idea here is that we allow the callback given to ResponseCache.wrap to decide whether its result should be cached or not. We do that by (optionally) passing a ResponseCacheContext into it, which it can modify.

2 files changed, 4 insertions, 4 deletions

diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index 2a13026e9a..f13a7c23b4 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -285,7 +285,7 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
             self.__class__.__name__,
         )
 
-    def _check_auth_and_handle(self, request, **kwargs):
+    async def _check_auth_and_handle(self, request, **kwargs):
         """Called on new incoming requests when caching is enabled. Checks
         if there is a cached response for the request and returns that,
         otherwise calls `_handle_request` and caches its response.
@@ -300,8 +300,8 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
         if self.CACHE:
             txn_id = kwargs.pop("txn_id")
 
-            return self.response_cache.wrap(
+            return await self.response_cache.wrap(
                 txn_id, self._handle_request, request, **kwargs
             )
 
-        return self._handle_request(request, **kwargs)
+        return await self._handle_request(request, **kwargs)
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index 043c25f63d..34206c5060 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -345,7 +345,7 @@ class ReplicationUserJoinedLeftRoomRestServlet(ReplicationEndpoint):
 
         return {}
 
-    def _handle_request(  # type: ignore
+    async def _handle_request(  # type: ignore
         self, request: Request, room_id: str, user_id: str, change: str
     ) -> Tuple[int, JsonDict]:
         logger.info("user membership change: %s in %s", user_id, room_id)